1. Field of the Invention
This invention is directed to an agricultural implement which includes combination subsoil sweep blades and deep soil ripper blades and more particularly to such an implement in which each sweep and ripper blade is attached to a common upright support and where the ripper is vertically adjustable relative to the sweep blade.
2. Description of the Related Art
Recently it has been customary, particularly in relatively low moisture crop cultivation operations, such as those performed in the American Great Plains, to perform low tillage or no tillage farming operations to promote continuous surface coverage to prevent wind and water soil erosion. To perform low tillage operations, relatively wide, V-shaped sweep blades have been developed which sweep along a path below the soil surface, at a shallow depth of, for example, 2" to 6". This insures that the top surface of the soil is relatively undisturbed, except for the passage of the supports upon which the sweeps are mounted. This provides weed control with a minimal amount of soil disturbance. At the same time, particularly after harvesting during dry soil conditions, it is necessary to periodically perform deep soil fracturing operations with soil rippers which extend to a depth of from 7" to 10", in order to loosen the hardpan soil to increase moisture absorption. This soil ripping or fracturing operation is usually performed either immediately before or after the sweep operation, which entails two complete passes with tractor and plow. Often these consecutive passes are made with the same implement, but with the sweep blades exchanged for ripper blades or vice versa. It is apparent that a big savings in both time and fuel requirements could be realized if the two operations could be performed simultaneously on the same pass. Furthermore, the use of a wide sweep plow blade, plowing the soil to a depth of 2" to 6", preceding a ripper plow blade, fracturing the soil to a depth of 7" to 10", allows the ripper to perform the fracturing operation with much less energy expenditure, thus providing an additional savings in fuel costs and/or allowing the plow to be pulled with a tractor of less horsepower.
A number of previous attempts have been made to combine sweeps and rippers in a single plow implement. For example, in U.S. Pat. No. 4,909,335 to Walt, Jr., a V-shaped sweep blade is mounted on a first shank which positioned on an implement frame ahead of a second shank upon which is mounted a deep tillage tool or ripper. While this arrangement represents a substantial improvement in time and energy savings, it requires that a special implement frame be used which provides an area to mount two or three separate vertically oriented shanks arranged in tandem.
U.S. Pat. No. 4,974,681 to Symonds teaches a subsoil tine or ripper arranged beneath a sweep blade with both the tine and sweep blade attached to a single shank. However, the tine does not appear to be adjustable vertically relative to the sweep blade, and the entire implement is designed for making a single, narrow pass through a pine forest or the like. The sweep blade is apparently intended for cutting tree roots ahead of the tine.
It is clear then, that a need still exists for a combination sweep and ripper plow in which an existing plow implement frame can be adapted to have the sweep blade and the ripper blade attached to a common shank. The ripper blade should be adjustable vertically relative to the sweep blade and, preferably, the ripper blade should be readily movable to a non-operative position for sweep operations which do not require soil ripping.